The present invention relates to a blend of polymeric materials comprising; (A) of from about 1 to about 80 percent by weight (based on the combined weights of Components A and B) of at least one substantially random interpolymer; wherein said interpolymer; (1) contains of from about 0.5 to about 50 mole percent of polymer units derived from; a) at least one vinyl or vinylidene aromatic monomer, or b) at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer, or c) a combination of at least one vinyl or vinylidene aromatic monomer and at least one hindered aliphatic or cycloaliphatic vinyl or vinylidene monomer; (2) contains of from about 50 to about 99.5 mole percent of polymer units derived from at least one aliphatic &agr;-olefin having from 2 to 20 carbon atoms; (3) has a melt index (I2) of from about 0.01 to about 100 g/10 min; and (4) has a molecular weight distribution (Mw/Mn) of from about 1.5 to about 20; (B) of from about 20 to about 99 weight percent based on the combined weights of Components A, and B of one or more engineering thermoplastics.